This invention relates to an optical disc recording system for recording data on a writable type optical disc and, more particularly, to an optical disc recording system of this type in which, when program information is recorded program by program separately and with interruption and table-of-contents (hereinafter sometimes abbreviated as "TOC") information is recorded later, information at a part-of-the-way or intermediate position (intermediate information) among position information necessary for producing the TOC information is recorded during each interruption at a position inside of a TOC area on the optical disc and this intermediate information is read when writing of program information is resumed for later utilization for generation of the TOC information thereby to save time required for collecting position information necessary for generation of the TOC information and thus shorten time required for generation of the TOC information.
Known in the art are writable type optical discs such as a DRAW (additional writing type) disc and an E-DRAW (erasable type) disc. The DRAW disc allows writing for only once and, in this disc, information pits are formed by, for example, burning off a metal recording film by heat generated by irradiation of laser beam. The E-DRAW disc allows rewriting of recorded data and includes one utilizing a magneto-optical recording system and one utilizing a phase change between a crystalline state and an amorphous state.
On these writable type optical discs are provided a program area and a TOC area (corresponding to a lead-in area in a Compact Disc) in the same manner as in a Compact Disc (hereinafter abbreviated as "CD") in a Compact Disc Digital Audio System.
Program information (i.e., data such as music data) is recorded, with position information (i.e., data representing position such as address, time and music number), in the program area of the optical disc. TOC information (corresponding to TOC in a Compact Disc) including, e.g., a program number, start time of each program, total program number and finish time of all programs is recorded in the TOC area. This TOC information is utilized for, e.g., random access.
In recording program information in the prior art writable type optical disc, positions at which each program information starts and ends are measured prior to recording, TOC information is formed on the basis of this data and this TOC information is attached at the head of the program information to produce a series of data and achieve recording at a stretch.
The TOC information cannot be written unless and until all program information to be written on an optical disc has been determined and the table of contents has thus been determined. For this reason, in a case where program information is recorded program by program separately and with interruption, it is not possible, as in the prior art recording system, to generate TOC information previously and attach it at the head of program information to achieve recording at a stretch. In the case of recording program information separately program by program with interruption, therefore, all program information on the disc must be reproduced after all program information has been recorded to obtain position information necessary for generating TOC information and produce TOC information to be recorded in the TOC area on the disc. It therefore takes about 60 minutes, for example, to obtain position information necessary for producing TOC information, if information of a full Compact Disc recording capacity is to be recorded. This results in the disadvantage that recording of TOC information in an optical disc takes unduly long time.
It is, therefore, an object of the invention to overcome the above described problem of the prior art optical disc recording system and provide an optical disc recording system in which, when program information is recorded program by program separately and with interruption and TOC information is recorded later, time for collecting position information necessary for producing TOC information is saved and recording time thereby is shortened.